Direct-acting engine



ilNrTEo STATES PATENT OFFICE.

JAMES KIDD, OF BUFFALO, NEW YORK.

DIRECT-ACTING ENGINE.

SPECIFICATION forming part of Letters Patent No. 528,299, dated October30, 1894. Application filed January 27, 1894- Serial No.498.211. (Nomodel.)

To aZZ whom it may concern:

Beit known that I, JAMES KIDD, a citizen of their Pistons; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichitappertains to make and use the same, reference being had to theaccompanying drawing, and to figures of reference marked thereon,whichform a part of this specification.

My invention relates to improvements in the arrangement and constructionof cylinders and their pistons of direct acting engines used inconnection with steam or compressed air engines,and is specially adaptedfor use in connection with rock-drills and steam-hammers or anymachinery driven by steam or compressed air which is subjected to severeshocks, or which require action with the least possible resistance andwear to the working parts.

The form of piston and cylinders to which my improvements are appliedconsists of a piston havinga narrow annular shoulder at the piston-rodend, a cylinder of uniform interior dimensions throughout its lengthhaving aninlet passage at one end for the admission of steam underpressure or' compressed air into the cylinder and against the annularshoulder of the piston for sending the piston forward, a single exhaustpassage leading therefrom which is alternately opened or closed by thepiston in its travel and a passage in the side wall of thecylinderopening at both ends into the cylinder for conducting the steam underpressure or the compressed air to the cylinder space in front of thepiston, to cause the forward stroke, the piston in its travelalternately opening and closing the ends of the passage in the side wallof the cylinder.

As at present constructed the piston in its travel, strikes both ends ofthe cylinder with damaging effect especially when used in connectionwith rock-drills. The object of my invention is to prevent this poundingof parts and to that end it consists in arranging the inlet-port and therear port in the passage in the side wall, in such manner that a tightspace is left at each end of the cylinder be yond these ports, toprovide a cushion of,

steam or compressed air at these points to prevent the contact of thepiston with the end walls of the cylinder.

The figure of the drawing represents my improved cylinder and piston incentral longitudinal section in which 1 is the cylinder having thesteam-tight head 2..at one end and the seat 3 at the other end for thepassage of the piston-rod 4, made steam-tight by the screw-threaded cap5 which holds the packing ring 6 in position around the pistonrod. Atthe end of the piston-rod at within the cylinder is the piston 7. Itwill be noted that the diameter of the piston-rod 4 is not much smallerthan that of the piston 7 which leaves the comparatively narrow annularshoulder 8 against which the pressure of the steam or compressed air inthe annular space 9 is exerted to cause the return stroke of the piston.The steam under boiler pressure or compressed air, is admitted to thisannular space 9 behind the piston 7 through the inlet 10 which entersthe cylinders at a point beyond its end, thereby leaving a tight spacefor a steam or air cushion to form and prevent the piston from, comingin direct contact with the end of the cylinder. The exhaust port 11 islocated just beyond the middle portion of the cylinder-as shown.

On the opposite side of the cylinder within the enlargement 12 islocated the longitudinal passage 13 having the front and rear ports 14and 15 respectively, which lead to the interior of the cylinder. Thefront port 14c is located about midway of the length of the cylinder andthe rear port 15 a short distance within the end of the cylinder toallow a tight space for a steam or air cushion the same as at the otherend.

In operatiop it will be seen that, in the drawing, the piston is aboutmidway of its travel. The steam under boiler pressure or the compressedair is admitted to the annular space 9 behind the piston and exertingpressure against the annular shoulder 8 of I00 the piston 7 forces itforward in the cylinder shutting the exhaust port 11 in its returntravel and opening the forward port 1 in the passage 13 just as itcompletes its return stroke. This permits the steam under boilerpressure or the compressed air, from the annular cylinder space 9 to beforced through the passage 13 and admitted through the rear port 15 justas the piston starts back on its forward stroke. This start is effectedby the cushion of compressed steam left in that end of the cylinder, itbeing assisted by the weight of the drill or hammer secured to thepiston rod, in case either a rock-drill or steam hammer is beingoperated and also prevents a concussion of parts and the consequentforcing open of the head 2. The forward stroke of the piston is madeagainst the'steam under boiler pressure or the compressed air, in theannular cylinder space 9'at the other end, which is provided with noexhaust-port, but this is effected by the expansion of the steam orcompressed air, admitted through port 15, and exerted against the entireend area of the piston 7, as against the back pressure exerted upon theannular shoulder 8 upon the other end of the piston, its aggregate areabeing very much smaller than the entire end area of the opposite end ofthe piston. In

this manner the piston is forced ahead upon its forward stroke until theexhaust port 11 is passed which releases the pressure and permits thepiston to commence its next return stroke as already described.

I claim- An improved form of cylinder and piston for steam or compressedair engines consisting essentially of a piston having a narrow annularshoulder at the piston rod end, a cylinder of uniform interiordimensions throughout its length having an inlet-passage entering thecylinder away from its end to provide a tight space for a steam or aircushion, a single exhaust passage leading therefrom which is alternatelyopened and closed by the piston in its travel and a passage in the sidewall of the cylinder, one end opening near the middle of the cylinderand the other one away from the end of the cylinder to pro vide a tightspace for a steam or air cushion, such passage conducting the steamunder pressure or the compressed air to the cylinder space in front ofthe piston to cause the return stroke, the piston in its travelalternately opening and closing the ends of the passage in the side wallof the cylinder.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JAMES KIDD.

IVitnesses:

FRANKLYN J. KIDD, W. '1. MILLER.

